The present invention relates to a magnetic recording medium having two magnetic layers. More particularly, it relates to a magnetic recording medium having an upper magnetic layer of a higher coercive force and a lower magnetic layer of a lower coercive force, which has improved sensitivity and frequency characteristics or high output over broad frequency bands with less noise.
It has been known that, in a magnetic recording medium having two magnetic layers, sensitivity and frequency characteristics at both low and high frequency bands can be improved by making a coercive force of the lower layer low and that of the upper layer high, that is, the output at the high frequency band can be improved by the upper magnetic layer having a higher coercive force and the output at the low frequency band can be improved by the lower magnetic layer having a lower coercive force. Such a magnetic recording medium is usually produced by first applying a magnetic paint composition containing magnetic particles of a relatively lower coercive force onto a base film, such as a polyester film and drying the composition to form the lower magnetic layer, and then applying a magnetic paint composition containing magnetic particles of a relatively higher coercive force onto the lower magnetic layer and then drying the latter composition to form the upper magnetic layer.
However, in such a conventional magnetic recording medium of this type wherein the, sensitivity and frequency characteristics at both the low and high frequency bands are improved by a lower layer of a lower coercive force and an upper layer of a higher coercive force, there is the drawback that the curve of the frequency characteristics slacks at medium band, i.e., the output at the medium band drops.